Autosampler

ABSTRACT

An autosampler for manipulating a specimen container into and out of a furnace of a parent instrument is disclosed. The autosampler has upper, lower and middle gripping fingers which grip and stabilize a crimped wire, which has a large bend therein. The middle gripping finger is positioned between and opposed to the upper and lower gripping finger and has a portion at one end thereof sized and shaped to receive the bend of the crimped wire. The gripping fingers grip and hold the crimped wire while a tray table moves to place the specimen container on a hook at the bottom of the crimped wire. If the specimen container is sealed, a hole may be punctured therein by a puncturing apparatus, which has a housing which is movable between an upper and lower position and biased toward the lower position. A pin is positioned inside the housing. When the specimen tray moves into the upper position, the sealed specimen container moves the housing from the lower position to the upper position thereby exposing the pin and causing it to puncture the sealed specimen container. An electrostatic discharge device which includes a housing having a channel thereabout is also provided. A high voltage source is electrically connected to a pin positioned inside the housing and in fluid communication with the channel for supply voltage to the pin and generating multiple free ions as a result thereof. Pressurized gas directs the free ions toward an electrostatic field to neutralize the ions therein.

CLAIM OF PRIORITY

[0001] This application claims priority from U.S. Provisional PatentApplication No. 60/122,992 filed Mar. 5, 1999.

FIELD OF THE INVENTION

[0002] The present invention relates to an automatic sampling deviceand, in particular, to a device that automatically transfers a samplecontainer from a sample tray to known laboratory analyzing equipment,for the examination of, for example, the heats of transformation of asample, and which transfers the sample container from the analyzingequipment to the sample tray.

BACKGROUND OF THE INVENTION

[0003] It is known to use thermal gravimetric analysis (TGA) systems toconduct thermal analyses of selected samples, also referred to herein asspecimens, in order to examine certain characteristics of the samples asa function of temperature. As it is sometimes necessary to carry outmeasurements on a large number of samples, it is desirable and known inthe art to mechanize the manipulation of the specimens. Suchmechanization is commonly referred to as autosampling.

[0004] One autosampler is shown in U.S. Pat. No. 5,398,556 to Lang. Langdiscloses a device having a vertical gripper member and a rotatablespecimen plate for holding a plurality of specimen containers. Aspecimen container is transferred to the measuring location in theparent machine (e.g., a TGA) by rotating the specimen plate so that thedesired specimen container is positioned under the gripper. Then, thegripper, which is driven by a motor, is lowered and gripping fingersattached to a gripping member grip the specimen container. The containeris then raised from the specimen plate by raising the gripping member.The specimen plated is then rotated until a recess in the specimen plateis located underneath the gripping member. Next, the gripping member islowered through the recess in the specimen plate and the specimencontainer is placed at the measuring location, which is directlyunderneath the gripper. The specimen container is then deposited on themeasuring location by releasing the gripper fingers.

[0005] A disadvantage of the gripper taught by the Lang patent is thatthe device is relatively complicated in that it has many moving partsand that if the motor over- or under-drives the gripper, an error couldoccur in the placement of the sample.

[0006] In conventional thermogravimetric analysis machines, samples areplaced in a crucible or sample container that is positioned in a furnaceon a platinum ribbon attached to an automatic recording balance.Conventional TGAs are disadvantageous because the platinum wire iseasily bent with even a very small force by the gripper when it movesthe crucible on and off the balance. After the platinum wire is bent, itis virtually impossible to move back into its original position. If thedevice is used with a bent wire, it is extremely difficult to accuratelyposition the crucible within the furnace. Further, the act of replacingthe platinum wire typically decreases the sensitivity of the machine anddetrimentally effects its performance.

[0007] Known autosamplers are also disadvantageous because staticelectricity may accumulate in the furnace area. This is frequently aserious problem which detrimentally effects analytical results. Thestatic buildup generally occurs on the surface of the glasswaresurrounding the TGA furnace and is aggravated by movement of theglassware over insulating material, such as an O-ring. The resultingelectrostatic fields attract the sample container to the surface of theglassware, thus moving the sample container off balance and jeopardizingthe advancement of the analysis. Additionally, static electricity maypull some of the sample from the sample pan if the sample pan containssome dust-like particles.

[0008] Devices and methods are known to reduce or eliminate staticelectricity. For example, there are solutions which may be wiped ontoglass surface areas. Unfortunately, these known solutions may leavebehind a residue which can undesirably build-up on the glass andadversely effect the test results. Alternately, an operator may point ahand-held ion generating device at the area. However, such isundesirable because it requires the operator to stay in the vicinity ofthe autosampler during the course of the sampling, which can be manyhours, and, because the static electricity is not visible, the operatormay miss the problem area. Additionally, radioactive emitters areavailable. However, these are disadvantageous because they have strictdisposal requirements.

[0009] As is known, conventional autosamplers comprise a sample traytable having a plurality of recesses for holding each of the samplecontainers in place while the analysis is being conducted. Conventionalsample tray tables, however, are disadvantageous because they do notfacilitate placement of the sample pan into the recess.

[0010] Sometimes it is necessary to work with sealed sample containers,such as when the contents of the sample container are volatile. If asample container is sealed, it is necessary to puncture the top of thesealed container prior to placing it into the furnace. Conventionalpuncturing devices are disadvantageous, however, because they haveseveral moving parts and are relatively complicated. Further,disadvantageously, it is sometimes necessary to puncture a samplemanually before it is loaded into the tray. When this is done, thesample sometimes loses some of its properties before being loaded intothe furnace.

[0011] What is desired, therefore, is an autosampler which has a gripperassembly that cooperates with a hanging wire, wherein the hanging wireis not easily bent or damaged and wherein the hanging wire may be easilyreplaced without reducing the sensitivity of the parent instrument,which is operably connected to an electrostatic discharge device, whichhas a sample tray table with recesses that facilitate placement of thesample container into the recesses, and which is operatively connectedto a safe and reliable puncturing device.

SUMMARY OF THE INVENTION

[0012] Accordingly, it is an object of the present invention to providean autosampler which has a gripper assembly that cooperates with ahanging wire which is durable and not easily damaged.

[0013] It is another object of the present invention to provide anautosampler which cooperates with a hanging wire assembly that can beeasily replaced without reducing the sensitivity of the parentinstrument.

[0014] It is still another object of the present invention to provide anautosampler which has a sample tray table with beveled edges and roundedrecess areas to facilitate placement of the sample pan into the recessesof the sample tray table.

[0015] It is yet a further object of the present invention to provide anautosampler which is operatively connected to an electrostatic dischargedevice that is safe, effective and easy to use.

[0016] It is still another object of the present invention to provide anautosampler which is operatively connected to a puncturing device whichhas no motorized parts and which is relatively inexpensive tomanufacture and simple to construct.

[0017] It is still a further object of the present invention to providean autosampler which is reliable, easy to use, and cost-effective tomanufacture and maintain.

[0018] To overcome the deficiencies of the prior art and to achieve theobjects and advantages listed above, an autosampler is disclosed whichcomprises'a novel gripping assembly which is uniquely sized and shapedto stabilize a crimped wire which hangs from an arm of a balance of theparent instrument. After the gripping assembly grips and stabilizes thewire, a tray table. which is positioned about the gripping assembly,moves vertically and rotationally to position a specimen container ontoa hook at the bottom of the crimped wire and substantially reverses itssteps to remove the container from the crimped wire.

[0019] The crimped wire is uniquely designed to be received by thegripping apparatus. The crimped wire has two ends defining an axistherebetween and has at least one point which is displaced from theaxis, i.e., the hanging wire is substantially bent at at least onelocation.

[0020] More particularly, the gripper assembly comprises upper, middleand lower gripping fingers, which are movable between an open and aclosed position. The upper and lower fingers each have a V-shapedportion at one end for receiving the crimped wire therein and aligningthe crimped wire above and below its bend. The middle gripping fingerhas two ends and is positioned between, and opposed to, the upper andlower gripping finger. The middle gripping finger has a portion at oneend thereof sized and shaped to receive the crimped wire at the bend.When the gripping fingers are in the closed position, they grip thecrimped wire and stabilize it while the specimen tray moves so as toconnect the specimen container to the hook of the crimped wire.

[0021] Additionally, the autosampler is operatively connected to anapparatus for puncturing holes into the top of a sealed specimencontainer. The puncturing apparatus comprises a housing, which isoperatively connected to the parent instrument and which is movablebetween an upper and a lower position. A spring biases the housing intothe lower position. A sharp object, such as a pin, is housed inside thehousing. When a sealed specimen container is positioned under the sharpobject, movement of the tray table to its uppermost position causes thecontainer to force the housing to move from the lower position to theupper position thereby exposing the sharp object. This causes the sharpobject to puncture the sealed specimen container.

[0022] Additionally, the autosampler is operatively connected to anelectrostatic discharge device which reduces or eliminates electrostaticfields which are formed on the surface of glassware of the furnace andon the surface of the autosampler tray and gripper assembly. Theelectrostatic discharge device comprises a housing which is removablyattached to the parent instrument; the housing has a channel thereabout.At least one pin, but preferably a plurality of pins, is positionedinside the housing and in fluid communication with the channel. A sourceof high voltage alternating current is electrically connected to eachpin and supplies voltage to the pins. This generates multiple free ionswhich cancel the electrostatic field. A source of pressurized gas, suchas nitrogen or air, is operatively connected to the housing and forcesgas through the channel and around the pins and directs the free ionstoward an electrostatic field to neutralize the ions therein.

[0023] The invention and its particular features and advantages willbecome more apparent from the following detailed description whenconsidered with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 is an isometric view of an autosampler, constructed inaccordance with the present invention;

[0025]FIG. 2 is a side isometric view of the autosampler shown in FIG.1, showing a crucible hanging from a hanging wire assembly and agripping assembly in the open position;

[0026]FIG. 3 is a side isometric view of the autosampler similar to theone shown in FIG. 2, wherein the autosampler has moved to a “mid”position;

[0027]FIG. 4 is a side perspective view of the balance of the parentinstrument, showing the hanging wire assembly on one end thereof;

[0028]FIG. 5 is a side plan view of the hanging wire assembly;

[0029]FIG. 6 is an isometric view of the gripper assembly in the closedposition;

[0030]FIG. 6A is a top view of the gripper assembly of FIG. 6;

[0031]FIG. 6B is a top view of the gripper assembly of FIG. 6 shown inthe open position;

[0032]FIG. 7 is a bottom perspective view of an electrostatic dischargedevice constructed in accordance with the present invention;

[0033]FIG. 8 is an exploded view of the top of the electrostaticdischarge device shown in FIG. 7;

[0034]FIG. 9 is an exploded view of the bottom of the electrostaticdischarge device shown in FIG. 7;

[0035]FIG. 10 is a schematic diagram of electrostatic discharge deviceshown in FIG. 7;

[0036]FIG. 11 is a top schematic view of a sample tray table shown inFIG. 1;

[0037]FIG. 12 is an enlarged and broken away view of a recess in thesample tray table shown in FIG. 11;

[0038]FIG. 13 is a cross-sectional view of a puncture device which isoperatively connected to the autosampler shown in FIG. 1, constructed inaccordance with the present invention; and

[0039]FIG. 14 is a top view of the autosampler shown in FIG. 1 with thecover removed for clarity.

DETAILED DESCRIPTION OF THE INVENTION

[0040] Referring to the drawings in detail, an autosampler is shown andgenerally designated by the reference numeral 10. It should be notedthat for the sake of clarity not all of the components and parts of autosampler 10 may be shown and/or marked in all the drawings. As used inthis description, the terms “up”, “down”, “top”, “bottom”, etc., referto autosampler 10 when in the orientation illustrated in FIG. 1.

[0041] Referring now more particularly to FIG. 1, autosampler 10 isdesigned to be used with, and operatively connected to, a parentinstrument 12, for example, a thermal gravimetric analysis (TGA)machine. As is known, TGA machines conduct thermal analyses of selectedsamples in order to examine certain characteristics of the samples as afunction of temperature. It should be understood that autosampler 10 maybe used with other analytical instruments known in the art, afterobvious modifications that will become apparent after reading thisdescription. Discussion herein has been limited to the TGA forconvenience only and is not intended to be limiting.

[0042] Before operations begin, operational data can be provided to acomputer (not shown) of the autosampler 10 by an operator through akeyboard (not shown) with a display means (not shown), all of which areknown in the art. Alternatively, the computer of the autosampler 10 maybe driven by a computer program provided by a host computer (not shown),such as the one marketed by Perkin-Elmer Corporation known in the fieldby the trademark Pyris 1™.

[0043] As is known, parent instrument 12 generally comprises a furnace14 (FIG. 3) for heating specimen container. Furnace 14 is operativelyconnected to Pyris 1 software, and capable of heating up to temperaturesof about 1000° C. or more. Furnace 14 comprises a conventional heatingelement 15 (FIG. 3) and is movable along a vertical axis between anupper and lower position. When in the uppermost position, glass top 16seals against O-ring 18.

[0044] As best shown in FIGS. 4 and 5, parent instrument 12 alsocomprises a conventional and extremely sensitive balance or weightmeasuring apparatus 20. Balance 20 has two arms 22, 24. A conventionaltare weight 26 hangs from one arm 24. Arm 22 contains a series of wiresor ribbons which serve to hold a specimen container 28 (FIG. 2).

[0045] More specifically, a glass sphere 30 is removably positioned ontop of a hollow glass tube 32 and held in place by flange 34 and anadhesive 36,such as rubber cement, which is known in the art. A ribbon38, preferably made of platinum, extends through the chamber of hollowglass tube 32 and is connected to sphere 30. Ribbon 38 is rotatable inthe direction shown by arrow 40. Ribbon 38 has a loop 42 formed at oneend thereof.

[0046] In conventional parent instruments, wire members which hold thespecimen container during the analysis have been known to break. Whenthe wire breaks or bends, it must be replaced. Disadvantageously, thesensitivity of the balance of prior art devices is typically damaged ordestroyed during the replacement process. Advantageously, and unlikeprior art instruments, the use of the removable adhesive 36 and flange34 to position platinum ribbon 38 renders ribbon 38 easily replaceable.Further, when ribbon 38 is replaced, the sensitivity of balance 20 isnot damaged or destroyed.

[0047] Crimped wire 46 having hook 44 is positioned in loop 42 of ribbon38. Crimped wire 46 can be made of any suitable material but ispreferably made of nichrome or quartz. Crimped wire 46 has two endsdefining an axis 48 therebetween. Advantageously, crimped wire 46 has atleast one point 50 which is displaced from axis 48, i.e. includes abend. In the preferred embodiment, the angle formed by members 52, 54 atlocation 50 is about 90°. Crimped wire 46 has hook 56 formed at the endthereof for connecting specimen container 28 (FIG. 2) thereto.

[0048] Referring in detail to FIGS. 1-3. autosampler 10 is removablyfixed and operatively connected to parent instrument 12. Autosampler 10comprises at least one specimen tray 58, also shown in FIGS. 11 and 12.Tray 58 has a plurality of recesses 60 for receiving specimen container28 (FIG. 2). Preferably there are at least 20 recesses, but it should beunderstood that as many recesses could be formed as necessary.

[0049] Each of the recesses is given a unique identifying number foreasy sample identification. At least one, and preferably all, of therecesses 60 has at least one beveled edge 62 to facilitate placement ofthe specimen container 28 therein (FIG. 12). Also, it is preferable thateach recess 60 be uniquely shaped so that the specimen container 28 isalways properly positioned and oriented therein. Still further, it ispreferred that at least one of the recesses of the specimen tray besubstantially rounded to facilitate placement of the specimen container28 therein.

[0050] Specimen tray 58 is movable via a conventional stepper motor 59and a slip clutch and electromagnetic brake assembly 61 between an upperand lower position as indicated by arrow 64 and rotatable in thedirection shown by arrow 66 about a central axis 68 (see FIGS. 2 and14). Any suitable stepper motor known in the art may be used. In theembodiment, a stepper motor having the following operationalcharacteristics is preferred: 12 volts DC; 0.3 amps; 2 phase; and 0.9mm/step.

[0051] A second stepper motor 63 (FIG. 14) swings autosampler 10 toward(FIGS. 1 and 2) and away from (FIG. 3) the specimen load position. Thisstepper motor may have the following operational characteristics: 12volts DC; 0.3 amps; 2 phase; and 0.9 mm/step. Autosampler 10 is attachedto the parent instrument 12 via a pivot shaft 65 (FIG. 1). Autosampler10 is movable between a loading and an unloading position and, when notloading or unloading, autosampler 10 moves to a “safe” location, i.e.,away from the load position, where the specimen is analyzed.

[0052] Movement by these two motors, together with a gripper motor 67(discussed below), allows gripping assembly 70 (discussed in detailbelow) to access each container 28, transfer it from the specimen tray58 and attach it to hook 56 of crimped wire 54, and return it to itsappropriate position on the sample tray 58 after the analysis iscompleted. It should be understood, however, that any suitable meansknown in the art may be used to move autosampler 10, such as mechanical,hydraulic or magnetic means, or combinations thereof.

[0053] Referring to FIGS. 2, 3, 6, 6A and 6B, autosampler 10 furthercomprises a gripper assembly 70 operatively connected to specimen tray58 and movable between an open position (shown in FIGS. 2, 3 and 6B) anda closed position (FIGS. 6 and 6A). When gripper assembly 70 is in theclosed position, it grips crimped wire 46 about the point 50 (FIG. 5) atwhich it is displaced from its linear axis, and stabilizes it while thespecimen tray 58 moves so as to connect the specimen container 28 to thecrimped wire 46.

[0054] More specifically, gripper assembly 70 comprises upper, middleand lower gripping fingers 72, 74, 76, respectively (each finger may notbe shown in all the drawings). Each finger 72, 74, 76 may be made of anysuitable material, however, they are preferably made of aluminum.

[0055] In one embodiment, the upper 72 and lower 76 gripping finger aresubstantially identical in design. Each gripping finger has two endswith a substantially V-shaped portion 80 cut therefrom for receivingcrimped wire 46 therein.

[0056] Middle gripping finger 74 is positioned between the upper andlower fingers 72, 76, respectively, and, as best shown in FIGS. 2, 6 and6B, opposes fingers 72, 76. Middle finger 74 has two ends and a portion78 at one end thereof sized and shaped to receive crimped wire 46 at thepoint 50 where crimped wire 46 is maximally displaced from its axis 48.As shown in FIG. 6A, when in the closed position, middle gripping finger74 cooperates with the upper and lower gripping finger 72, 76, to gripand stabilize crimped wire 46 so that specimen container 28 may bepositioned on hook 56.

[0057] Middle gripping finger 74 is designed to push against crimpedwire 46 at the location of the angle formed by members 52, 54. It shouldbe understood that any suitable size angle could be formed by members54, 56 and any suitable cutout portion of finger 74 could be used solong as middle finger 74 cooperates with fingers 72, 76 to stabilizecrimped wire 46 while specimen container 28 is loaded and unloaded.

[0058] Gripping fingers 72, 74, 76 are biased to a closed position.Fingers 72, 74, 76 may use any suitable means to move between an openand closed position, such as hydraulic, mechanical and magnetic meansand/or combinations thereof. In one embodiment, a motor 67 (FIG. 14)turns a cam (not shown) which simultaneously activates the fingers.Although any suitable conventional motor may be used, in one embodiment,a motor having the following operational characteristics is used: 12volts DC; 0.3 amps; 2 phase; and 0.9 mm/step.

[0059] As discussed above, static build up generally occurs on thesurface of the glassware surrounding the TGA furnace 14, and isaggravated by movement of the glassware 16 over insulating material,such as O-ring 18. The resulting electrostatic fields negativelyinfluence the readings of the highly sensitive microbalance 20 of theparent instrument 12 because the sample container 28 is moved off-centerdue to its attraction to the surface of the glassware. Advantageously,parent instrument 12 comprises an electrostatic discharge device 82,which is best shown in FIGS. 3, 7, 8 and 9, which substantially reducesand/or eliminates the electrostatic fields described above.

[0060] Electrostatic discharge device 82 comprises a housing 84 which isoperatively and removably attached to parent instrument 12, and is mostpreferably mounted above the TGA furnace 14. The housing 84 surroundsthe uppermost portion of the furnace assembly 14 and is therefore inclose proximity to the region of static buildup.

[0061] Discharge device 82 comprises at least one, and preferably aplurality of, substantially sharp objects 86, such as heavy-duty metalpins (see FIG. 9). Each of the pins 86 are substantially equidistantlypositioned about a metallic ring 88 through a circular cavity 87 (FIG.7). Each cavity 87 is sufficiently deep so that the pins 86 are notdirectly exposed to the touch and the walls of each cavity 87 are angledto direct the ions toward the electrostatic field. As the pinpoints weardue to normal use over extended periods of time, the production of ionsat each point may diminish. Advantageously, each pin 86 may be easilyreplaced to restore full production of ions.

[0062] A voltage source is electrically connected to each pin 86 forsupplying voltage to the pin 86 and generating multiple free ions as aresult thereof. Any suitable voltage amount may be used: in the mostpreferred embodiment about 5,000-6,000 VAC is used (see FIG. 10).

[0063] Referring again to FIGS. 8 and 9, above the metallic ring 88 is agas plenum 90 that feeds a low-pressure gas stream from a gas source 94into each cavity 87 which is in fluid communication therewith.Preferably, compressed air or nitrogen is used. The gas stream causesthe positive and negative free ions generated at the pinpoints 86 to bepropelled downward toward the furnace 14. The combined flow from eachcavity 87 (FIG. 7) effectively blankets the furnace area 14 with freeions that neutralize electrostatic fields on the glassware above andbelow O-ring 18, i.e., the top half of the furnace, and on the surfaceof the autosampler tray 58 and gripper assembly 70.

[0064] A schematic diagram of the electrostatic discharge device 82 isshown in FIG. 10. The low-pressure gas source 94 is connected fromwithin the analytical instrument 12 to the gas plenum within the housing84 through a port in the housing 84. Any suitable, standard flexibletubing and fittings may be employed to connect the gas source 94 to thehousing 84. A second port connects the high voltage, alternating currentsource 98 to the metallic ring 88 within housing 84 via resistiveelement 99. The second port is comprised of a long insulating tube 96that extends into the discharge device 82. Conventional resistiveelement 99, nominally about eight megohms, is housed inside tube 96 andlimits electrical current flow into the pinpoint 86 should a shortcircuit occur or in the event that the operator of the TGA 12 comes intocontact with any of the metallic elements of device 82. Conventionalhigh voltage AC transformer 98, housed inside the parent instrument 12,is advantageously designed to limit self-generation of ions within itsown environment.

[0065] Activation of both the low-pressure gas source 94 and the highvoltage transformer 98 are controlled by a microprocessor 100,electrically and operatively connected to interface electronics 102housed inside the parent instrument 12. Discharge device 82 may beactivated manually or automatically by entering the appropriate commandinto the Pyris 1 software from the keyboard of the host computer.Preferably, the gas and high voltage supplies 94, 98, respectively, areturned on immediately prior to the separation of the upper and lowerhalves of the furnace 14. While the furnace 14 is separated, theionization device 82 remains on so that components of the furnace 14 andthe sample handling area are flooded with ions.

[0066] Advantageously, the discharge device 82 is designed so that itautomatically stops operating if the furnace 14 remains open (as shownin FIG. 3) for a long period of time, such as greater than threeminutes. This reduces the amount of ozone produced by the dischargedevice 82 and reduces the operator's exposure to the high voltage withinthe housing assembly 84.

[0067] When the furnace assembly 14 is commanded to close, theionization device remains on, or turns on again as the case may be. Thetime to close the furnace 14 is programmable, thereby allowing adequatetime to discharge lingering electrostatic fields. All timing relatedchanges are made by modifying the control firmware (not shown) withinthe microprocessor 100.

[0068] Parent instrument 12 also comprises an apparatus 104 forpuncturing holes into the top of a sealed specimen container 28, whichis best shown in FIG. 13. Puncturing apparatus 104 comprises a housing106, operatively connected to parent instrument 12, and uses theautosampler's sample tray 58 up/down movement to move to and from apuncture position (FIG. 13) and a rest position (not shown); that is,puncturing apparatus 104 is movable via the sample tray 58 between anupper and lower position. Steel spring 108 biases housing 106 into thelower position. It should be understood that any suitable means may beused to bias housing 106 into the lower position.

[0069] A sharp or pointed object 110, such as a pin, is housed insidethe puncturing device housing 106 for puncturing a hole into the top ofa sealed specimen container 28. Any suitable strong, sharp object may beused. In the preferred embodiment, a steel pin is used.

[0070] A slot 112 is formed at the bottom of the housing 106 and issized and shaped to receive a hook or handle 114 (FIGS. 2, 3 and 13) ofspecimen container 28.

[0071] In operation, when the specimen tray 58 (FIGS. 1-3 and 11) movesinto the upper position, the sealed specimen container 28 forces thehousing 106 to move from the lower position to the upper positionthereby exposing pin 110 and causing it to puncture the top of thesealed specimen container 28.

[0072] A method for handling and transferring specimen containers 28generally follows the operation of autosampler 10 discussed above andcomprises the following steps. First, an operator programs autosampler10 and loads specimen containers 28 containing specimens onto specimentray 58.

[0073] Gripper 70 begins each session in the open position and tray 58is in the lowermost position and in a “safe” position, which is farthestfrom furnace 14. Autosampler 10 is then instructed by the operator viasoftware to begin a session, i.e., to pick-up a particular samplecontainer 28 and to load it into furnace 14.

[0074] Autosampler 10 swings via stepper motor 63 from the “safe”position to a “mid” position, which is between the “safe” position andthe “loading” position. At the “mid” position, tray 58 rotates viastepper motor 59 to the desire sample position, which positions thepredetermined container 28 immediately to the left of hook 56 of crimpedwire 46.

[0075] Autosampler 10 then swings until it is in a “loading” position, aposition in which it is directly over the lowered furnace 14. Grippingfingers 72, 74, 76 then close via stepper motor 67 around crimped wire46 and stabilize and align it. Tray table 58 then raises up, rotatescounterclockwise to deposit the hook or handle 114 of container 28 ontohook 56 (see FIGS. 2 and 3). After the container 28 is properlypositioned on crimped wire 46, the tray table 58 lowers to its lowermostposition via stepper motor 59 and gripping fingers 72, 74, 76 move viastepper motor 67 to their normally open position. Then, autosampler 10swings to its “mid” position where the host computer conducts a quicksafety check and then autosampler 10 swings to the “safe” position viastepper motor 63.

[0076] Next, furnace 14 moves from its lowermost position to the upperposition and encloses specimen container 14 therein by forming a tightseal at O-ring 18. Then, the furnace is activated, the temperatureinside the furnace rises to the pre-selected temperature, and thedesired thermogravametric analysis takes place. The weight differentialis measured by balance 20 and pertinent data is recorded by the hostcomputer.

[0077] After the appropriate test has been completed, the furnace 14cools down and moves to its lowermost position. Autosampler 10 thenprepares to unload the specimen container 20 from the furnace 14. First,autosampler 10 swings from its “safe” position to the “mid” position.Tray table 58 rotates via stepper motor 59 until the recess forreceiving container 28 is just to the right of specimen container 28 asit hangs on wire 46, and autosampler 10 rotates to the “load” position.Gripper fingers 72, 74, 76 then close via stepper motor 67 around wire46 and stabilize it. Tray 58 then moves via stepper motor 59 to itsuppermost position. Table 58 then rotates via stepper motor 59 clockwiseand picks up sample container 28. Table 58 then moves to its lowermostposition and gripping fingers 72, 74, 76 open via motor 67 and remain inthe normally open position. Autosampler 10 then swings to its “mid”position where a quick safety check is conducted and then swings againto its “safe” position via motor 63.

[0078] If specimen container 28 is sealed, its top must be puncturedprior to its being placed in furnace 14. Puncturing device 104 (FIGS. 1and 13) punctures a hole in the top of sealed container 28 wheninstructed by an operator via instructions entered into the hostcomputer. Puncturing device 104 operates in the manner discussed above.

[0079] After autosampler 10 has been properly programmed and loaded, itadvantageously operates without further human operator assistance.Further, the autosampler 10 has the ability with the Pyris 1™ program,when properly programmed, to abort an analysis if problems occur withthe transfer of a specimen container 28 and to generate an error messagewhich is displayed on the display screen of the host computer (notshown).

[0080] In its most preferred embodiment, autosampler 10 is capable ofloading up to 20 samples without operator assistance, thus, freeing theoperator to perform other tasks. Advantageously, because of the safetyfeatures built into the autosampler 10, the operator does not need to bein the vicinity of the autosampler 10 while it is working. Thus, theoperator may load autosampler 10 near the end of the work day, and uponreturning to work the next day, find the results of the analysis. As aresult, autosampler 10 saves the operator much time and energy.

[0081] It should be understood that the foregoing is illustrative andnot limiting and that obvious modifications may be made by those skilledin the art without departing from the spirit of the invention.Accordingly, reference should be made primarily to the accompanyingclaims, rather than the foregoing specification, to determine the scopeof the invention.

What is claimed is:
 1. An apparatus for manipulating a specimencontainer comprising: a parent instrument comprising a crimped wirehaving two ends defining an axis therebetween, the crimped wire havingat least one point which is displaced from the axis; an autosampler,operatively connected to the parent instrument, comprising: a gripperassembly movable between an open and a closed position; at least onespecimen tray positioned about the gripper assembly and having aplurality of recesses therein for receiving at least one specimencontainer, the specimen tray movable between an upper and a lowerposition and rotatable about a central axis; and wherein when thegripper assembly is in the closed position it grips the crimped wireabout the point at which it is displaced from the axis and stabilizes itwhile the specimen tray moves so as to attach the specimen container tothe crimped wire.
 2. The apparatus of claim 1 wherein the gripperassembly further comprises: an upper and a lower gripping finger, eachfinger having two ends, each finger having one end with a substantiallyV-shaped portion for receiving the crimped wire therein; and a middlegripping finger having two ends, the middle gripping finger positionedbetween and opposed to the upper and lower gripping finger and having aportion at one end thereof sized and shaped to receive the crimped wireat the point where the crimped wire is displaced from its axis; andwherein the middle gripping finger cooperates with the upper and lowergripping fingers to grip and stabilize the crimped wire.
 3. Theapparatus of claim 1, wherein at least one of the recesses of thespecimen tray has at least one beveled edge to facilitate placement ofthe specimen container.
 4. The apparatus of claim 1, wherein at leastone of the recesses of the specimen tray is shaped so that the specimencontainer is properly positioned therein.
 5. The apparatus of claim 4,wherein at least one of the recesses of the specimen tray issubstantially rounded.
 6. The apparatus of claim 1 further comprising anapparatus for puncturing a hole into the specimen container, thepuncturing apparatus comprising: a housing operatively connected to theparent instrument, the housing movable between an upper and lowerposition and biased toward the lower position; a pointed object housedinside the housing; and wherein when the specimen tray moves into theupper position, the specimen tray moves a specimen container positionedin one of the recesses of the specimen tray and under the pointed objectupward forcing the housing to move from the lower position to the upperposition thereby exposing the pointed object and causing it to puncturethe specimen container.
 7. The apparatus of claim 6 wherein thepuncturing apparatus further comprises a spring, housed inside thehousing, for biasing the housing toward the lower position.
 8. Theapparatus of claim 7 wherein the puncturing apparatus housing includes aslot therein, the slot sized and shaped to receive a hook of thespecimen container.
 9. The apparatus of claim 1 further comprising anelectrostatic discharge device comprising: an electrostatic dischargedevice housing attached to the parent instrument, the electrostaticdischarge device housing having a channel thereabout; at least onesubstantially sharp object positioned inside the electrostatic dischargedevice housing and in fluid communication with the channel; a voltagesource, electrically connected to the at least one substantially sharpobject for supplying voltage thereto and generating multiple free ionsas a result thereof; a source of pressurized gas for generating a gasstream, the pressurized gas source operatively connected to theelectrostatic discharge device housing and in fluid communication withthe channel, for forcing gas through the channel and around the at leastone substantially sharp object; and wherein the gas stream directs thefree ions toward an electrostatic field to neutralize ions therein. 10.The apparatus of claim 9 wherein the at least one substantially sharpobject comprises about seven substantially sharp objects substantiallyequidistantly spaced about the channel.
 11. The apparatus of claim 9wherein the voltage source supplies about 5,000 volts of alternatingcurrent.
 12. The apparatus of claim 9 wherein the gas comprises air. 13.The apparatus of claim 9 wherein the gas comprises nitrogen.
 14. Aninstrument for conducting analysis of a plurality of sealed specimencontainers, the instrument comprising: an instrument housing; at leastone specimen tray adjacent to the instrument housing, the at least onespecimen tray having a plurality of recesses therein and movable betweenan upper and a lower position; and an apparatus for puncturing at leastone hole into a sealed specimen container, the puncturing apparatuscomprising: a puncturing apparatus housing removably attached to theinstrument housing, the puncturing apparatus housing movable between anupper and a lower position and biased toward the lower position; and asharp object housed inside the puncturing apparatus housing, whereinwhen the specimen tray moves toward the upper position a sealed specimencontainer positioned in a recess of the specimen tray and under thesharp object forces the puncturing apparatus housing to move from thelower position to the upper position thereby exposing the sharp objectand causing it to puncture the sealed specimen container.
 15. Theapparatus of claim 14 wherein the puncturing apparatus further comprisesa spring, housed inside the puncturing apparatus housing, for biasingthe housing toward the lower position.
 16. The apparatus of claim 15wherein the puncturing apparatus housing includes a slot therein, theslot sized and shaped to receive a hook of the sealed specimencontainer.
 17. A device for discharging an electrostatic field on atleast one component of a parent instrument, the parent instrument havinga housing, the electrostatic field discharging device comprising: anelectrostatic discharge device housing attached to the parent instrumenthousing, the electrostatic discharge device housing having as channelthereabout; at least one sharp object positioned inside theelectrostatic discharge device housing and in fluid communication withthe channel; a voltage source electrically connected to the at least onesharp object for supplying voltage thereto and generating multiple freeions as a result thereof; a source of pressurized gas for generating agas stream, the pressurized gas source operatively connected to theelectrostatic discharge device housing and in fluid communication withthe channel, for forcing gas through the channel and around the at leastone sharp object; and wherein the gas stream directs the free ionstoward an electrostatic field to neutralize ions therein.
 18. Theelectrostatic field discharging device of claim 17 wherein the at leastone sharp object comprises about seven sharp objects substantiallyequidistantly spaced about the channel.
 19. The electrostatic fielddischarging device of claim 16 wherein the gas comprises air.
 20. Theelectrostatic field discharging device of claim 16 wherein the gascomprises nitrogen.
 21. The electrostatic field discharging device ofclaim 17 wherein the voltage source supplies about 5,000 volts ofalternating current.